Genetically predisposed individuals, who make up about 10% of the population, become hypersensitized (allergic) to antigens from a variety of environmental sources to which they are exposed. Those antigens that can induce immediate and/or delayed types of hypersensitivity are known as allergens. (King, T. P., Adv. Immunol. 23: 77-105, (1976)). Anaphylaxis or atopy, which includes the symptoms of hay fever, asthma, and hives, is one form of immediate allergy. It can be caused by a variety of atopic allergens, such as products of grasses, trees, weeds, animal dander, insects, food, drugs, and chemicals.
The antibodies involved in atopic allergy belong primarily to the IgE class of immunoglobulins. IgE binds to mast cells and basophils. Upon combination of a specific allergen with IgE bound to mast cells or basophils, the IgE may be cross-linked on the cell surface, resulting in the physiological effects of IgE-antigen interaction. These physiological effects include the release of, among other substances, histamine, serotonin, heparin, a chemotactic factor for eosinophilic leukocytes and/or the leukotrienes, C4, D4, and E4, which cause prolonged constriction of bronchial smooth muscle cells (Hood, L. E. et al. Immunology (2nd ed.), The Benjamin/Cumming Publishing Co., Inc. (1984)). These released substances are the mediators which result in allergic symptoms caused by a combination of IgE with a specific allergen. Through them, the effects of an allergen are manifested. Such effects may be systemic or local in nature, depending on the route by which the antigen entered the body and the pattern of deposition of IgE on mast cells or basophils. Local manifestations generally occur on epithelial surfaces at the location at which the allergen entered the body. Systemic effects can include anaphylaxis (anaphylactic shock), which is the result of an IgE-basophil response to circulating (intravascular) antigen.
Japanese cedar (Sugi; Cryptomeria japonica) pollinosis is one of the most important allergic diseases in Japan. The number of patients suffering from this disease is on the increase and in some areas, more than 10% of the population are affected. Treatment of Japanese cedar pollinosis by administration of Japanese cedar pollen extract to effect hyposensitization to the allergen has been attempted. Hyposensitization using Japanese cedar pollen extract, however, has drawbacks in that it can elicit anaphylaxis if high doses are used, whereas when low doses are used to avoid anaphylaxis, treatment must be continued for several years to build up a tolerance for the extract.
The major allergen from Japanese cedar pollen has been purified and designated as Sugi basic protein (SBP) or Cry j I. This protein is reported to be a basic protein with a molecular weight of 41-50 kDa and a pI of 8.8. There appear to be multiple isoforms of the allergen, apparently due in part to differential glycosylation (Yasueda et al. (1983) J. Allergy Clin. Immunol. 71: 77-86; and Taniai et al. (1988) FEBS Letters 239: 329-332. The sequence of the first twenty amino acids at the N-terminal end of Cry j I (SEQ ID NO: 18) and a sixteen amino acid sequence (SEQ ID NO: 19) at the carboxy terminus have been determined (Taniai supra).
A second allergen has recently been isolated from the pollen of Cryptomeria japonica (Japanese cedar) (Sakaguchi et al. (1990) Allergy 45:309-312). This allergen, designated Cry j II, has been reported to have a molecular weight of approximately 37 kDa and 45 kDa when assayed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under non-reducing and reducing conditions, respectively (Sukaguchi et al., supra). Cry j II was found to have no immunological cross-reactivity with Cry j I (Sakaguchi (1990) supra; Kawashima et al. (1992) Int. Arch. Allergy Immunol. 98:110-117). Most patients with Japanese cedar pollinosis were found to have IgE antibodies to both Cry j I and Cry j II. however, 29% of allergic patients had IgE that only reacted with Cry j I and 14% of allergic patients had IgE that only reacted with Cry j II (Sakaguchi (1990) supra). Isoelectric focusing of Cry j II indicated that this protein has a pI above 9.5, as compared to pI 8.6-8.8 for Cry j I (Sakaguchi (1990) supra).
In addition to hyposensitization of Japanese cedar pollinosis patients with low doses of Japanese cedar pollen extract, U.S. Pat. No. 4,939,239, issued Jul. 3, 1990 to Matsuhashi et al., discloses a hyposensitization agent comprising a saccharide covalently linked to a Japanese cedar pollen allergen for hyposensitization of persons sensitive to Japanese cedar pollen. This hyposensitization agent is reported to enhance the production of IgG and IgM antibodies, but reduce production of IgE antibodies which are specific to the allergen and responsible for anaphylaxis and allergy. The allergens used in the hyposensitization agent preferably have an NH.sub.2 -terminal amino acid sequence of Asp-Asn-Pro-Ile-Asp-Ser-X-Trp-Arg-Gly-Asp-Ser-Asn-Trp-Ala-Gln-Asn-Arg-Met- Lys-, wherein X is Ser, Cys, Thr, or His (SEQ ID NO: 18). Additionally, Usui et al. (1990) Int. Arch. Allergy Appl. Immunol. 91: 74-79 reported that the ability of a Sugi basic protein (i.e., Cry j I)-pullulan conjugate to elicit the Arthus reaction was markedly reduced, about 1,000 times lower than that of native Sugi basic protein and suggested that the Sugi basic protein-pullulan conjugate would be a good candidate for desensitization therapy against cedar pollinosis.
The Cry j I allergen found in Cryptomeria japonica has also been found to be cross-reactive with allergens in the pollen from other species of trees, including Cupressus sempervirens. Panzani et al. (Annals of Allergy 57: 26-30 (1986)) reported that cross reactivity was detected between allergens in the pollens of Cupressus sempervirens and Cryptomeria japonica in skin testing, RAST and RAST inhibition. A 50 kDa allergen isolated from Mountain Cedar (Juniperus sabinoides, also known as Juniperus ashei) has the NH.sub.2 -terminal sequence AspAsnProIleAsp (SEQ ID NO: 25) (Gross et al., (1978) Scand. J. Immunol. 8: 437-441) which is the same sequence as the first five amino acids of the NH-.sub.2 terminal end of the Cry j I allergen. The Cry j I allergen has also been found to be allergenically cross-reactive with the following species of trees: Cupressus arizonica, Cupressus macrocarpa, Juniperus virginiana, Juniperus communis, Thuya orientalis, and Chamaecyparis obtusa.
Despite the attention Japanese cedar pollinosis allergens have received, definition or characterization of the allergens responsible for its adverse effects on people is far from complete. Current desensitization therapy involves treatment with pollen extract with its attendant risks of anaphylaxis if high doses of pollen extract are administered, or long desensitization times when low doses of pollen extract are administered. Thus there is a pressing need for the development of compositions and methods that could be used in detecting sensitivity to Japanese cedar pollen allergens or other immunologically related allergens or in treating sensitivities to such allergens with reduced side effects. The present invention provides materials and methods having one or more of these utilities.